feat(nix): add LSPs/formatters/linters/DAPs to common.nix

Replaces Mason entirely (phase p6 of the nix migration will rip out
mason-tool-installer and friends). The set tracks the previous
ensure_installed list in nvim's lsp.lua, with five niche tools dropped
per the migration plan:

  - groovy-language-server, npm-groovy-lint
  - nginx-language-server, nginx-config-formatter
  - systemdlint

systemd-lsp is renamed to systemd-language-server (the nixpkgs attr
name). codelldb is replaced by lldb-dap (upstream successor, ships with
pkgs.lldb); dap configs switch in phase p6.

Drops jre, basedpyright, cargo, rustc from vm.nix — they only existed
to work around Mason quirks on Ubuntu 20.04 (uv-python wheel
incompatibility, source-build needs). With Mason gone, basedpyright
comes from nixpkgs cleanly on both profiles.

Phase 5 of the nix-on-host migration plan.

2 files changed, 50 insertions, 12 deletions

diff --git a/nix/common.nix b/nix/common.nix
index b6a8493..9bfe2d6 100644
--- a/nix/common.nix
+++ b/nix/common.nix
@@ -89,6 +89,56 @@ in
     claude-code
     github-copilot-cli # NB: pkgs.copilot-cli is AWS Copilot, NOT this
 
+    # ── LSPs / formatters / linters / DAPs ─────────────────────────────────
+    # Replaces Mason entirely (phase p6 of the nix migration rips out
+    # mason-tool-installer). The set tracks the previous
+    # `ensure_installed` list in dot_config/nvim/lua/plugins/lsp.lua, with
+    # five niche tools dropped: groovy-language-server (Mason-only build,
+    # upstream stale), npm-groovy-lint, nginx-language-server,
+    # nginx-config-formatter, systemdlint (all rarely-edited domains;
+    # losing them is acceptable).
+
+    # LSPs
+    actionlint
+    autotools-language-server
+    basedpyright
+    bash-language-server
+    dockerfile-language-server-nodejs
+    gh-actions-language-server
+    just-lsp
+    lua-language-server
+    neocmakelsp
+    ruff
+    rust-analyzer
+    systemd-language-server
+    taplo
+    typescript-language-server
+    vscode-langservers-extracted   # cssls + html + jsonls + eslint
+    yaml-language-server
+
+    # Formatters
+    mdformat
+    nodePackages.prettier
+    shfmt
+    stylua
+
+    # Linters
+    codespell
+    hadolint
+    nodePackages.jsonlint
+    markdownlint-cli
+    selene
+    shellcheck
+    shellharden
+    stylelint
+    typos
+    yamllint
+
+    # DAPs / debuggers — `lldb-dap` (from pkgs.lldb) is the upstream
+    # successor to vscode-lldb's `codelldb`. dap configs in
+    # plugins/debug.lua target it via `type = "lldb"`.
+    lldb
+
     # Zsh and plugins (loaded from $HOME/.nix-profile/share/... by the
     # shared zshrc; nix-profile path is preferred, system path is the
     # fallback for un-bootstrapped states).
diff --git a/nix/vm.nix b/nix/vm.nix
index d003b6e..7445b7b 100644
--- a/nix/vm.nix
+++ b/nix/vm.nix
@@ -18,18 +18,6 @@
   };
 
   home.packages = with pkgs; [
-    # ── Mason-driven LSP carve-outs (removed by phase p6 once Mason is
-    #    gone and LSPs come from common.nix directly). Kept here for
-    #    now so the VM keeps working between phases. ───────────────────────
-    jre                  # Mason's groovy-language-server (headless Java)
-    basedpyright         # Mason's pypi distro can't install on Ubuntu 20.04
-                         # (manylinux_2_28 wheels, uv's python rejects)
-    # Rust toolchain for Mason packages whose only install source is
-    # `cargo install` (shellharden). The Arch host has these via pacman;
-    # on the VM Mason needs cargo+rustc on PATH or it bails with ENOENT.
-    cargo
-    rustc
-
     # ── Rootless podman ─────────────────────────────────────────────────────
     # The nix `podman` is wrapped to find these helpers via /nix/store
     # paths, so we don't need to write a containers.conf for